Transcutaneous Auricular Vagus Nerve Stimulation for Insomnia in Survivors of Childhood Acute Lymphoblastic Leukemia

This pilot study will assess the usefulness and potential effectiveness of using transcutaneous auricular vagus nerve stimulation (tVNS) for treating insomnia in adult survivors of childhood acute lymphoblastic leukemia (ALL). Participants will be randomized to receive either active (verum) or inactive (sham) nightly stimulation using a non-invasive earbud device over two time periods: 2 weeks and 8 weeks. The study will assess adherence to the intervention and estimate its effects on sleep quality, stress, and neurocognitive function. Primary Objective: Aim 1: To determine a) short-term and b) long-term feasibility of tVNS in terms of participation in ALL Survivors with moderate to severe insomnia. Aim 2: To estimate the effect size of tVNS on sleep quality, stress, and neurocognitive outcomes in ALL survivors with insomnia. Exploratory Objectives Aim 1: To investigate the onset of tVNS effect via actigraphy measures over the intervention epoch. Aim 2: To estimate the effect size of genetic variants on sleep quality within verum tVNS.

Approximately 40 adult survivors of childhood ALL enrolled in the SJLIFE cohort will be recruited. Eligible participants must have moderate to severe insomnia (ISI ≥8). The intervention involves nightly use of a tVNS device for 20 minutes before sleep. Participants will be randomized to receive either active or sham stimulation. Feasibility will be assessed based on adherence rates, and efficacy will be estimated using subjective (PSQI, ISI) and objective (actigraphy, CNS Vital Signs) measures. Exploratory analyses will examine the onset of tVNS effects and the influence of genetic variants (BDNF rs6265, COMT rs4680) on treatment response.

Inclusion Criteria: * Survivor of Acute Lymphoblastic Leukemia (ALL) * Enrolled on SJLIFE * Participant was less than 21 years of age at time of diagnosis. * Age 20-50 years at the time of enrollment * Insomnia Severity Index \>=8 (Proxy \>=8) confirmed prior to enrollment * Access to home Wi-Fi and Smartphone * Participant is able to speak and understand the English language * Participant is able and willing to give consent Exclusion Criteria: * Unable to understand the details and requirements of the study (at the discretion of the PI) * Female participants who are pregnant or planning to become pregnant * Presence of implanted electrical medical devices (i.e. pacemaker) * Currently taking medication intended to treat neurocognitive impairment (i.e. stimulants) or medications prescribed for seizure management * History of skin irritation or other issues during stimulation of inner ear * Currently utilizing a technological intervention for a sleep disorder (e.g. CPAP) * Medications and behavioral practices (white noise, night-time yoga, etc) are acceptable as long as the insomnia is persistent. * History of a contraindicated health condition including: * Syncope (CTCAE \>2) * Cardiac dysrhythmia (CTCAE \>2) * Vascular Disease (CTCAE \>2) * Coronary Artery Disease (CTCAE \>2) * Active contraindicated heath condition including: * Cranial Nerve Disorder (CTCAE \>2) * Neuropathy (Cranial Nerves) (CTCAE \>2) * Neuralgia (Cranial Nerves) (CTCAE \>2) * Overt Cerebrovascular Accident (CTCAE \>2) * Seizures (Any in most recent 1 year * Currently enrolled or participating in any other neurostimulation or neuromodulation ancillary research studies